Cocoa, including cocoa liquor and cocoa powder (cocoa solids), is the essential ingredient of chocolate and other sweet and savoury foods having a chocolate-like flavour such as biscuits, desserts and beverages. Cocoa powder is the solid, “non-fat” (conventionally 10-12 or 20-22 wt. % fat) component of cocoa liquor which is obtained by fermenting, de-shelling and roasting cocoa beans and grinding the resulting roasted nibs (the other component of cocoa liquor being cocoa butter).
In the manufacture of cocoa, steaming and alkalizing steps may be included. The steaming step may be included prior to the roasting, and prior to alkalization, for the purpose of debacterizing the cocoa beans as received after fermentation. Alternatively, the steaming or wetting step introduces water into the cocoa beans or nibs, making them more flexible to withstand the roasting without mechanical damage.
The alkalizing step in general is employed for several purposes. On the one hand, it produces a broad variety of differently coloured cocoa powders for specific applications. On the other hand, it increases the pH of the product, rendering it more soluble in an aqueous surrounding, which is important if the product is dispersed, e.g., in a beverage. Finally, the alkalizing step may improve the flavour of the final cocoa (cocoa liquor or cocoa powder).
Both the alkalizing step and the roasting step can be applied on the cocoa bean, on the cocoa nib after removal of the shell, on the cocoa liquor, on the cocoa cake after pressing off the cocoa butter, or on the cocoa powder after pulverization of the cocoa cake. Also, the sequence of the roasting and alkalizing steps may be changed, depending on equipment and functionality of the finished product.
According to U.S. Pat. No. 4,784,866, cocoa liquor and an alkalizing agent in aqueous phase are mixed and heated in a closed vessel under a pressure of from 1 to 3 atm at a temperature of less than 110° C., while introducing an oxygen-containing gas. This process is said to improve the taste and dispersibility of cocoa and to provide alkalized cocoa having a red coloration for obtaining a wider range of colour shades of red and brown.
According to WO 2006/008627, cocoa powder with better taste and brighter and more intense red colour can be obtained by a process comprising the steps of wetting cocoa nibs with water up to a water content of at least 5 wt %, grinding the wetted cocoa nibs, shaping the ground nibs to form shaped agglomerated cocoa particles, and roasting the cocoa particles at a temperature of between 80 and 160° C.